In the process by which milk and other dairy products are fortified with vitamins, it is extremely important to accurately regulate the quantity of vitamin concentrates added to the milk. Failure to maintain vitamin concentrate delivery at the proper level has untold effects irrespective of whether the vitamin concentrate delivered is above or below the specified range. Recent well-publicized cases have illustrated the risks of overfortification. For example, vitamin D intoxication or hypervitaminosis D is caused by excessive vitamin fortification of dairy milk. Dr. Jacobus, et al., "Hypervitaminosis D Associated With Drinking Milk", The New England Journal of Medicine (Apr. 30, 1992). Other problems include hypercalcemia, hypercalciuria, urinary tract stones, extraskeletal calcifications and malfunctions of the kidneys and other organs. As a result, the operation of dairy vitamin concentrate addition is under increasing regulatory scrutiny.
Current vitamin delivery systems possess several inherent weaknesses including: imprecise control, difficulty of calibration, incompatibility with equipment sanitation operations, inadequate backpressure resistance, and lack of independent automatic verification of volume pumped, among others.
Prior delivery systems have, until recently, been quite difficult to calibrate and adjust flow rates. The typical calibration procedure involved repeated mechanical adjustments to match a desired pumping rate. More recent models have incorporated digital controls of greater sophistication which greatly simplify the calibration and operation of the equipment, and permit interfaces with computerized control systems. These models feature variable-speed motors with keypad controllers, which permit one-touch operation and screens which display either flowrate or total volume pumped. The delivery system of the present invention utilizes this type of control apparatus.
Many of these more sophisticated prior devices, however, rely on a peristaltic or "tubing" pump mechanism for product delivery due to its simplicity and relatively low initial cost. This type of pump uses sequential compression of a light, flexible hose to move the product fluid by peristalsis. These hoses tend to wear out rapidly under this constant flexure, requiring frequent replacement. The required hose flexibility also restricts peristaltic pumps to use in systems with static pressure no higher than 25 psig, obviating their use in higher-pressure systems since the tubing will swell or burst under those conditions.
In contrast, the most commonly used pumps which can operate in high-pressure systems feature a ceramic piston to pump the vitamin concentrate, but do not typically offer the automated features required for simple and precise operation and control. No system has previously been used which combines easy operation and control with the pressure-handling capabilities of a piston pump.
Electrical components, particularly the motors and controllers, of prior delivery systems are also susceptible to the wet environment found in all dairy plants. Due to the need for absolutely sanitary conditions in processing fluid milk products, the plant areas are frequently and thoroughly sprayed with water mixed with sanitizing solution. Unless special accommodations are made, the majority of units in current use will fail when subjected to these conditions, requiring replacement of motors, controllers, or both. The typical solution has been either to dismantle and remove the system prior to washdown or to encase the pumps in a costly, inconvenient waterproof enclosure.
Additionally, prior delivery systems are by and large not compatible with either computers or standard control systems.
Further, prior art delivery systems do not provide independent verification of pumped volumes. Developing regulations require monitoring and recording of actual vitamin volumes used for fortification in light of several cases of injury in which milk was improperly fortified. Some prior art systems utilize a "metering" monitor/totalizer which senses the number of revolutions (per minute and total) made by the pump drive motor. This approach is susceptible to errors of several type in several locations including in the tubing (broken or burst), in the calibration (discrepancy between pump drive RPM and volume), or if there is a lack of product or air pockets in the lines. Any of these can result in faulty volume readings due to the strict dependence on the reliability of the drive and upstream components. Independent verification of flow resolves these issues of uncertainty. Furthermore, prior vitamin delivery systems do not provide a simple, accurate, precise method of documenting volumes of vitamins pumped. Documentation will be essential to meeting increasingly stringent regulations requiring fortification traceability and verification.
The vitamin concentrate delivery system of the present invention overcomes all of the foregoing problems. The pump itself is driven by a variable-speed motor connected to a digital electronic controller operated through a digital keypad. The pump system is calibrated by a simple, one-step procedure which is prompted by the controller. The digital controller/variable speed pump drive system also simplifies flow rate adjustment.
The system of present invention features a ceramic piston pumping mechanism. This allows utilization of higher-grade tubing and high pressure pumping of the vitamin concentrate as required. This type of mechanism delivers a fixed volume of product per piston cycle (stroke) and is negligibly affected by variations in fluid viscosity.
The pump, controller, flow sensor, and flow transmitter of the present invention are built to NEMA-4 (waterproof) standards and are thereby impervious to water and cleaning materials. This provides for safe and reliable setup, maintenance, and repair of the system despite the daily sanitation activities in the plant. The pump flowmeter and tubing of the present invention can themselves be sanitized by simple pumping of sanitizing solution through the system.
The controller of the present invention accepts control signals from any typical digital control system or computer control device.
The vitamin delivery system of the present invention also eliminates the deleterious effects of pump and flow stream failures through the incorporation of a highly accurate flowmeter in the line between the pump and the vitamin injection point. Preferably, the flowmeter used is a magnetic flowtube or other type of flowmeter of a size which accommodates the extremely low flowrates at which the dairy concentrates are delivered. This flowtube is independently calibrated and provides a true independent record of vitamin delivered.
The vitamin delivery system of the present invention is also adapted to be connected by hardware to a remote chart recorder, distributed control system, and other typical instrumentation and control systems which can be used to totalize product flows and provide a hard copy record of volume actually pumped over a given period of time. With increasing government oversight, this feature helps the user to meet their record-keeping responsibilities.